Scale for testing the position of the center of gravity of rapidlyrotating parts of machinery



March 17. 1925. 1,529,951

N OF THE CENTER OF GRAVITY 0F RAP H. HORT IDLY SCALE FOR TESTING THE POSITIO ROTATING PARTS OF MACHINERY Filed Jan. 2, 1925 Patented Mar. 17, 1925.

UNITED STATES v v 1,529,951 PATENT QFFICE.

HERMANN Hon'r, or JESS-EN, GERMANY, ASSIGNOR r rerun. nurr AKTIEN- GESELLSGHAFT, or EssEN-o-N-THERUHR, GERMANY.

SCALE FOR TESTING THE POSITION OF THE CENTER OF GRAVITY O'F BAPIDLY- I ROTATING PARTS OF MACHINERY.

Application filed January 2, 192a Serial No. 610,287.

To all whom it may concern..- Be it known that LTIERMANN Honr, re-

siding at Essen, Germany, a citizen of the German Republic, have invented a certain ing the position of the center of gravity ofrapidly rotating parts of machinery and has for its object to provide a knife-edge scale which is, more particularly, adapted for testing parts of machinery of the kind which are fastened to a shaft projecting by a considerable amount beyond the hub of the re spective part at both sides thereof.

In the drawing: Fig. l is a front elevation, partly in section, of an embodiment of the subject matter of the invention,

Fig. 2 is a section-on the line 22 of 1, seen from the left, and I Fig. 3 is a view, similar to Fig. 1, of a modified form of a detail.

A designates the part of machinery to be tested and A the shaft on which the part of machinery is fastened and Which projects by a considerable length beyond the hub of the part at both sides of the same. B are two bearing bodies which form each a separate structure and in which the shaft A is mounted for rotation at both sides of the hub of the machinery part A. Each bearing body B is provided with'a lmife-edge b which extends in the'direction of the axis of the bearing and by means of which the body to rotate easily in the bearing bodies B,

same are provided each'with two rollers E mounted for rotation on fixed shafts and supporting the shaft A The rollers E are arranged at a considerable height above the knife-edges 6 so that, under the action of the gravity, the bearing bodies B along with the machinery part A may only take a position of unstable eopuilibriunronthetwoknife edge bearings b Each outer head face ofthe bearing bodies B is provided with a reading mark (Fig. 1) and a circular graduation 7 which serve to determine the,

different angular positions into which the machinery part A may be turned on the bearing rollers E. The circular g-raduations f are formed on abipartite ring F each adapted to be'clamped to the shaft A 'by means of screws f Each bearing body B is further provided with a cap 6 adapted'to bear on the shaft A and to be so tightly clamped to the latter by means of bolts that the shaft A will be securel held against any rotation on the rollers f in every angular position.

Attached to the stands 0 at both sides of the shaft A are brackets 0 which are proing bodies B are adapted to bear by means of bearing faces 6 (Fig. 1). The brackets 0 further carry adjustablescrews 0 against each of which is placed under the pressure of a spring J (Fig. 1) and guided in the bearing bodies B. Every bolt H possesses a head 71. which serves as a support for one end of the corresponding spring J and by means of which the bolt may abut against a stop-face 'b" (Fig. 1) of the bearing body under the pressure ofthe spring, said stop-face. determining the front limit position of the bolt H. The other ends of the springs J which are all of the same strength, bear against set-screws K by means 'ofwhich they may be put under a preliminary tension in such a manner that they will exert equal forces on thebolts H when these are in their front limitpositi'on. Every bolt H carries a pointer 7L indicating'in ,every position of the bolt H at a double graduation b (Fig 2) the force at which the corresponding spring J .is acting on the bolt.

'Moreover, every bearing possesses at both sides of a middle plane extending through the bearing edge of the knife-edge and the axis of rotation-ofthe shaft A a tubu lar water level L (Fig. 1) the air bubble of which balances when the middle plane of thebearing body B is ina vertical position. In this vertical position of the middle plane, the axes of each set-screw 0 and corbears a bolt H which responding bolt H will constitute a straight line, all of'these straight lines lying syinbodies bymeans of the bolts Z2 metrically with relation to the. middle plane. Finally, every bearing body B is provided at both sides of its middle plane with a sup porting face 6 for receiving weights M.

In order to test the-p'osition-of the center shaft A inany angular position at both sides of the bearing bodies 13 closely beside the same. After the bearing'bodies' B have i been turned on the shaft A into an angular position in: which the air bubbles ofthe 1 ing body B with-relation to the axis ofthe knife-edge bearing 6 0 1- Therefore, if the waterlevelsl will balance, the caps Z2 are tightened by meansof the bolts 6* to such a degree that the"bearing bodies and the -machinery part are "seem-ed against relative rotation. The bearing bodies B along with the machinery part-A; are now-cautiously "lo-wered'with theknifeedges b ontfo the seatsc and propped by the set-screws G in such a manner as to cause the air bubbles of the "water levels L to continue balancing.

=previously'put under the samepreliminary tension by means of the set-screws K, will then exert force's of equal strength 'on the bolts Hyso that thepropping forces which ai'e'e-Xerted on each bearihg body B by the set-screws which serve as'abutments for the bolts H; are in equilibrium at the bearcenter of gravity of the machinery'part A to be tested llGS'lll the axis Ofl'Ottt-tlOil, the

1 bearing bodies B will remain in' their condition of 'equilibrium indicated by the water levels L when the set-screws G are screwed backwards and thus withdrawn from the ford the first, the bearing bodies B. will, if

the center of gravity lies for. instance en the left side, incline towards the: left upon unscrewingthe set-screws G, this being imane'chately indicated by tlHGIWZItQI lQVQlS L. In; this case, the bearlng'bodies are first readjusted by means of the set-screws G in such a manner that the air bubbles of the iwater levels Lt will balance after loosening the caps '6 the machinery part A 18 turned with relation-to the bearingbodies-B by a certain amount, whereupon the bearing caps are again tightened. The set-screws G are then unscrewed again and it is watched whether the air bubbles of the water levels will again indicate a"deflection. If this occurs thedescribedoperation-will be repeated until the machinery part during its adjustment with relation to the bearing bodies B,1will come into an angnlar position in which its center of gravity lies in the middle plane of the bearing bodies B, which plane extends through the axis of rotation of the machinery part and the bearing.- edges :of the knife-edges 6 In this case, thebear- '1 ing bodies B willie-main in their position of equilibriumupon unscrewing the set-screws G, so that the air bubblesof the water levels L will not change their position; The hear- "ing bodies 13 are then fixed again by means 10f the screws Grand the machinery part A rotated with relation .to the" bearing bodies by exactly 90, which can be read by. means of one of the two marks .6 at the corresponding graduation f' whereupon the machinery part LlS again securely clamped to the bearings B by tightening the caps 6 The machinery part A possesses now a high overweight on one side, for the. equalization of which the :tension 10f the springs J situated on the heavy side of the machinery part is increased by a corresponding amount x-throughtheintermediary of the set-screws so that, upon-unscrewing the set-screws G, the air bubbles of the water levels lJwill balance. The difference between thenumber indicated by the pointers 7L2 atthegraduations 6 ion the heavy side of themaohi-nery :partand the number to be read at the grad- 1 nationsb on the other side will then constitute a measure for the mass that has to be wremoved from the heavy: side of the mach incry part :in' order to displace the center of gravity into the. axis of rotation. After this mass has been-removed, the springs J are agaiir adjusted in :such a manner: as to cause the pointers 7 to indicate equal numbers at the; giaduations'7) both at the right and at i the left side. levels L are-thus caused to balance when the set-screws G have been unscrewed; indicat- 1 ing thereby that theeenterof gravity now x'situ'ated in the axisof rotation.

Instead ofputting the springs J under a "higher tension ,on the heavy side of the 'machinery part for the purpose of deter- .mining' the mass to be removed from that side,=?as described, weights M of suitable size wmay beplacedon the faces 5 of the opposite side.

i The working with the described knifeedge scaleiwil'l beconsiderably facilitated -when choosing conditions of the kind-under which the bearing' bodiesrB together with --the machinery part A will always be re- The air bubbles of the water i iii turned into their position of equilibrium under the action of the springs J, when they are resting so as to be freely movable in their position of equilibrium on the knife-edge bearings If, and artificially moved from distance between the springs and the axis of the knife-edge bearings so large as'to exceed a certain limit value determined by the conditions of equillbrlum. Also in c se a stable condition of equilibrium is pro dueed in the way indicated, itwill be possible to obtain by the use of sufficiently weak springs J a scale which is always sufliciently sensible for determining the smallest distances of the centers of gravity.

In some cases, the limit value which the distance of the springs J from the axis of the knifeedge bearingshas to exceed, becomes inconveniently large. A stable condition of equilibrium may then bev attained by interposing betweenthe bearing bodies B and the brackets c a double-armed lever each of a sufficiently large ratio oftrans mission, such as shown f. i. by Fig. 3. In this figure, i? denotes the short and N the long arm of the lever which is mounted on a knife-edge 0* of the corresponding bracket 0 The bearing body B bears on theshort lever arm N through the intermediaryof a set-screw b which corresponds to the setscrew 0 The bolt H with the pointer if,

the springJ and the set-screw K are, in this I case, not arranged on the bearing body B but on the bracket 0 in a casing c fastened to the same, this casing being provided with a graduation 0 corresponding to the graduation 6 and co-operating "with the pointer 71 The bolt H, which bears on the long lever arm N will transmit the power of the springs J to the bearing body B in such a manner that the effect of the spring will be increased in accordance with the ratio of transmission of the lever N, N As regards the spring action, the arrangenient-according to 3 is therefore equal to an arrangement according to Figs. 1 and 2 with which the distance between the springs J and the axis of the knife-edge bearings is increased in a proportion equal to the ratio of transmission of the lever N, N, and it is therefore adapted for use in cases in which, with the arrangement according to Figs. 1 and 2, the requisite distance between the springs J and the axis of the knife-edge hearings would become too large.

lVithout departing from the spirit of the invention, the caps and bolts 1) may be dispensed with. In this case, prior to the lowering of the machinery part A onto the scale, the bearing bodies 13 resting on the seats a are adjusted in such a manneras to cause the air bubbles of the water levels to balance, whereupon the machinery part A together with the shaft A 'is placed on the rollers E. i

Claims: i i

1. A knife-edge scale for testing the posi-' 1 tion of the center of gravity of a rotary ma chine part, said part belng mounted ona relatively fixed shaft, comprising a scale stand a plurality of bearing bodies, aligned knife-edge bearlngs between said bearing bodies and said standwhereby said bearing bodies are supported on said stand, said shaft being supported in said bearmgbodies above and parallel to said knife. bearings, and reslhent propping members interposed between said bearing bodies and said stand,

said propping members acting on said bearing bodies in planes removed from said knife-edge bearings, the strength of said propping members being so small as to allow of an accurate static testing operation.

2. A knife-edge scale fol-testing the position of the center of gravity ofa rotary machine part, said part being mounted on a relatively fixed shaft, comprising a-scale stand, a plurality of bearing bodies, aligned knife-edge bearings between said bearing bodies and saidstand whereby saidbearing bodies are supported on said stand, said shaftbeing supported in said bearing bodies above and parallelto said knife bearings, resilient propping members interposed between said bearing bodies' andsaid stand, said propping members "acting on said bearing bodies in planes removed from said force when said machine part is not inequilibrium.

3. A knife-edge scale for testing the position of the center of gravity of a rotary machine part, said part being mounted on a relatively fixed shaft, comprising a scale stand, a plurality of independent bearing bodies, aligned knife-edge bearings between said bearing bodies and said stand whereby said bearing bodies are supported on said stand, said. shaft being supported in said bearing bodies above and parallel to said knife bearings, resilient propping members interposed between said bearing bodies and said stand, said propping mem-- hers acting on said bearing bodies in planes removed from said knife-edge bearings, the strength of said propping members being so small as to allow of an accurate static testing operation, and means on'each of said bearing bodies for indicating the state of: f it sition of the center of'zgravityof a rotary knife-edge bearings between said bearing machine part, said: part being mounted on bodies and saidzstandwhereby said bearing a relatively'iixed' shaft, comprising-a scale bodies are; supported on: saidnstand, I said stand, a plurality of bearing bodies, aligned shaft being supported in said bearing bodies knife-edge bearings between said bearing 'above'and parallel to said knife bearings, bodies and said stand whereby said bearing emeans for resiliently propping said bearing bodies are: supported on: said stand, said bodies, and unequal-arm levcrs'interposed shaft being supported insaid bearing bodies between the bearing bodies and said propabove' and parallel to said; knife bearings, ping means, thelong arms of said levers beresilient propping members interposed being engaged by saidpropping means.

tween said'bearing bodies and said stand, 7. A' knife-edge scale for testing the po- Cil 'sai'diprop 'iing members acting on said bearsition of the center of gravity of a rotary in'g bodies in' planes removed from. said machine part, saidpart being mounted on knife-edge bearings,-the strength ofsaid a relatively fixed shaft, comprising a scale propping members being so small as to stand, a plurality of bearing bodies, aligned allow of an accurate static testing operaknife-edgebearings between said bearing tion,z means for adjusting said propping bodies and said stand whereby-said bearinembers for compensating the unbalancing ing bodies are supported on said stand, said force when said machine'part is notin equishaft being supported in said bearing bodies librium, and indicating means operated by above and "parallel to said knife bearings, said resilient'propping members for=measurmeai1s for resiliently propping said bearing the unbalancing force. sing bodies,liquid levels carried by said bear- 5. A knife edgeiscale for testing the poingbodies, andset-screws arranged between sition of the center of gravity of a rotary said bearingbodies and said scale stand for machine part, said part being mounted on adjusting said liquid levels;

a relatively fixed shaft, comprising a 'scale '8. A knifesedge scale for testing the postand, a plurality of bearing bodies, aligned sition of the center of gravity of a rotary knife-edge bearings between said bearing machine part, said part being-mounted on bodies and said stand whereby' said :beara relativelyfixe'd shaft, comprising a scale 30 ing bodies are supported on said standg said stand, a plurality of bearing bodies, aligned shaft being supported in said bearing bodies knife-edge bearings between said bearing above and parallel to said knife -bearings, bodies and saidstand whereby said bearmeans for resiliently propping said bearing ing bodies are supported on said stand, said bodies, and reduction means between sa-id shaft being supported in said bearing bodies means for stepping-down the action of the means for resiliently propping said bearing unbalancing force when said machine part is bodies,'andfaces onsaid bearing bodies for not in equilibrium. receiving balancing weights.

6. A knife-edge scale for testing the poi The foregoing specification signed at 40 sition of the center of gravity of a rotary i'Cologn'e, Germany, this 8th day of Decemmachine part, said part being mounted on her, 1922. a relatively fixed shaft, comprising a scale stand, a plurality of bearing bodies, aligned EIERMANN HORT.

bearing bodies and saidresilient propping above .and parallel to said knife bearings, I 

